Cyanate resin blends and radomes including them

ABSTRACT

Certain embodiments are directed to cyanate resin blends comprising, for example, a mixture of a cyanate monomer and a cyanate oligomer. The resin blends are effective to provide a dielectric constant of less than 2.7, a glass transition temperature of at least 150° C. and a moisture absorption of less than 1.5%. Radomes using the resin are also described.

TECHNOLOGICAL FIELD

This application is related to resin blends. More particularly, certainembodiments described herein are directed to cyanate resin blendssuitable for use in many instances such as, for example, a radome andsystems including radomes.

BACKGROUND

A radome is a structure that encloses and protects an antenna. Thestructure is generally weatherproof and protects the underlying antennafrom the elements, from being contacted by personnel or from damage fromexternal factors such as wind or temperature.

SUMMARY

In some aspects, a radome comprising a plurality of plies coupled toeach other is provided. In some embodiments, at least one of theplurality of plies comprises a substrate and a cured resin blendproduced from an effective amount of a cyanate monomer and an effectiveamount of a cyanate ester oligomer to provide a dielectric constant ofless than 2.7, a glass transition temperature of at least 150° C., inparticular at least 175° C. and a moisture absorption of less than 1.5%for the radome. In certain instances, the radome may further comprise aloss tangent of less than 0.004.

In some examples, the monomer of the radome is one or more of a compoundof formula (I)-(IV)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl andwherein R³ and R⁴ of formula (I) are independently selected fromhydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to 6 carbonatoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

In other embodiments, the monomer may comprise one or more of a compoundhaving a formula (V)-(IX)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl, andwherein R³ and R⁴ of formula (VII) and (IX) are independently selectedfrom hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to 6 carbonatoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Inother instances, the monomer may be selected from dicyclopentadienylbisphenol cyanate ester monomers.

In certain instances, the oligomer is a cyanate ester oligomercomprising two or more monomeric units each selected from a compoundhaving the formula (I)-(IX) or at least one dicyclopentadienyl bisphenolcyanate ester monomer. In some embodiments, the cyanate monomercomprises a bisphenol dicyanate group and the cyanate ester oligomercomprises a diphenylcyanate group. In other embodiments, the monomer ispresent from about 30-70 weight percent and the oligomer is present fromabout 70-30 weight percent (where the weight percent of the two resinsadds to 100 weight percent). In some examples, the resin blend maycomprise at least one phenol added to the resin blend. In otherexamples, the resin blend may comprise at least one metal catalyst,e.g., an acetylacetonate catalyst, added to the resin.

In certain configurations, the substrate of the radome comprises one ormore of a woven fabric, a non-woven fabric, a ceramic, a plastic, aglass, a fiberglass, a nylon, a polyester, a polyethersulfone, anaramid, a polyethylene, a polypropylene, a polyolefin, a polyimide, apolyamide, a polyamide-imide, a polyphenylene sulfide, a carbon, acarbon black, a graphite, a diamond, a polybenzimidazole, apolybenzoxazole or a halocarbon.

In some embodiments, the effective amount of the monomer by weightexceeds the effective amount of the oligomer by weight. In someinstances, the radome further comprises a loss tangent of less than0.004. In additional instances, the radome may comprise an insulationmaterial disposed on the inner surface of the radome.

The radomes, prepregs and the resins described herein can include one ormore toughening agents, such as thermoplastics (e.g. polysulfone,polyethersulfone, polyimide, polyethers, polyphenylene ethers,polyarylates), elastomers (e.g. copoly butadiene-acrylonitrile,polysiloxanes), and core-shell rubbers (CSR).

In an additional aspect, a radome comprising a plurality of pliescoupled to each other, in which at least one of the plurality of pliescomprises a substrate and a cured resin produced from an effectiveamount of a cyanate monomer selected from monomers of formula (I)-(IX)and dicyclopentadienyl bisphenol cyanate ester monomers to provide adielectric constant of less than 2.7, a glass transition temperature ofat least 150° C., in particular at least 150° C., in particular at least175° C. and a moisture absorption of less than 1.5% for the radome.

In another aspect, a prepreg comprising a plurality of plies coupled toeach other, in which at least one of the plurality of plies comprises asubstrate and a resin blend comprising an effective amount of a cyanatemonomer and an effective amount of a cyanate ester oligomer to provide acured resin comprising a dielectric constant of less than 2.7, a glasstransition temperature of at least 150° C., in particular at least 175°C. and a moisture absorption of less than 1.5%. In some embodiments, themonomer of the prepreg may comprise any of those monomers of formula(I)-(IX) as noted herein. In some embodiments, the oligomer is a cyanateester oligomer comprising two or more monomeric units each selected froma compound having the formula (I)-(IX) or dicyclopentadienyl bisphenolcyanate ester monomers. In some embodiments, the prepreg comprises abisphenol dicyanate group and the cyanate ester oligomer comprises adiphenylcyanate group. In additional examples, the monomer is presentfrom about 30-70 weight percent and the oligomer is present from about70-30 weight percent (where the weight percent of the two resins adds to100 weight percent). In some examples, at least one phenol added to theresin blend of the prepreg. In other examples, at least one metalcatalyst, e.g., an acetylacetonate catalyst, added to the resin blend ofthe prepreg.

In certain configurations, the substrate of the prepreg comprises one ormore of a woven fabric, a non-woven fabric, a ceramic, a plastic, aglass, a fiberglass, a nylon, a polyester, a polyethersulfone, anaramid, a polyethylene, a polypropylene, a polyolefin, a polyimide, apolyamide, a polyamide-imide, a polyphenylene sulfide, a carbon, acarbon black, a graphite, a diamond, a polybenzimidazole, apolybenzoxazole or a halocarbon.

In some embodiments, the effective amount of the monomer by weight inthe prepreg exceeds the effective amount of the oligomer by weight inthe prepreg. In other embodiments, the prepreg further comprises a losstangent of less than 0.004. In some instances, the prepreg may comprisea covering coupled to at least one of the plies of the prepreg.

In some aspects, a prepreg comprises a plurality of plies coupled toeach other, in which at least one of the plurality of plies comprises asubstrate and a resin comprising an effective amount of a cyanatemonomer selected from monomers of formula (I)-(IX) anddicyclopentadienyl bisphenol cyanate ester monomers to provide a curedresin comprising a dielectric constant of less than 2.7, a glasstransition temperature of at least 150° C., in particular at least 175°C. and a moisture absorption of less than 1.5%.

In another aspect, a resin blend comprising an effective amount of acyanate ester monomer and an effective amount of a cyanate esteroligomer to provide a cured resin comprising a dielectric constant ofless than 2.7, a loss tangent of less than 0.004, a glass transitiontemperature of at least 150° C., in particular at least 175° C. and amoisture absorption of less than 1.5% is described. In other aspects,the resin blend may comprise an effective amount of at least two cyanatemonomers and an effective amount of a cyanate ester oligomer to providea cured resin comprising a dielectric constant of less than 2.7, a losstangent of less than 0.004, a glass transition temperature of at least150° C., in particular at least 175° C. and a moisture absorption ofless than 1.5%. The monomers and oligomers of the resin blend may be anyof those monomers described herein, e.g., the monomers may comprise acompound of formula (I)-(IX) or dicyclopentadienyl bisphenol cyanateester monomer, and the oligomer may comprise two or more monomeric unitswhere at least one of the monomeric units comprises a monomer of formula(I)-(IX).

In an additional aspect, a resin comprises an effective amount of acyanate ester monomer selected from monomers of formula (I)-(IX) anddicyclopentadienyl bisphenol cyanate ester monomers to provide a curedresin comprising a dielectric constant of less than 2.7, a loss tangentof less than 0.004, a glass transition temperature of at least 150° C.,in particular at least 175° C. and a moisture absorption of less than1.5%.

In some aspects, a system comprising a radome as described herein and anelectronic device covered by the radome is provided. In some instances,the electronic device comprises an antenna, is part of a radar or sonarsystem, or is part of a communication system. In other instances, theradome is sized and arranged to be placed on an aircraft, a ship, a hullof a ship, e.g., immersed in the water during operation of the ship orabove the water surface during operation of the ship. Where theelectronic device takes the form of a communication system, thecommunication system may be selected from the group consisting of Wi-Fisystems, Bluetooth systems, radio systems, cellular communicationsystems and satellite systems.

In other aspects, a satellite comprising a transmitter/receiver and aradome as described herein is disclosed. In additional aspects, anautomotive vehicle comprising a transmitter/receiver configured tocouple to a bumper of the vehicle, the vehicle further comprising aradome as described herein is provided. In some aspects, an aircraftcomprising a radar system and a radome as described herein is provided.In some instances, the radar system is positioned in a nose cone or anundersurface of the aircraft. In other aspects, a ship comprising aradar system and a radome as described herein is provided. In someinstances, the radar system is positioned external to the hull of theship and beneath the water surface in operation of the ship. In otherinstances, a submarine comprising a sonar system and a radome asdescribed herein is provided. In some embodiments, the sonar system ispositioned external to the hull of the submarine.

In other aspects, a method of producing a radome comprises disposing aresin blend as described herein on a substrate, and polymerizing thedisposed resin to provide a radome comprising a dielectric constant ofless than 2.7, a glass transition temperature of at least 150° C., inparticular at least 175° C. and a moisture absorption of less than 1.5%.In some embodiments, polymerizing the disposed resin also provides aradome with a loss tangent of less than 0.004. In some instances, thepolymerizing step comprises permitting the resin to polymerize by ringopening metathesis polymerization at a first temperature for a firstperiod and then completing polymerization of the resin at a secondtemperature, higher than the first temperature, for a second period. Incertain examples, the method may comprise adding at least one additiveto the resin before or after polymerization of the resin. In otherexamples, the additive is a flame retardant, a smoke suppressant or apigment.

Additional features, aspect, examples and embodiments are described inmore detail below.

BRIEF DESCRIPTION OF THE FIGURES

Certain embodiments are described with reference to the accompanyingfigures in which:

FIG. 1 is an illustration of a prepreg comprising a plurality of plies;

FIG. 2 is another illustration of a prepreg comprising a plurality ofplies where two of the plies comprise different materials;

FIG. 3 is an illustration of a prepreg comprising a protective layer orcovering;

FIG. 4 is an illustration of a radome comprising an antenna; and

FIG. 5 is an illustration of a radome covering an electronic device.

It will be recognized by the person of ordinary skill in the art, giventhe benefit of this disclosure, that certain dimensions or features inthe figures may have been enlarged, distorted or shown in an otherwiseunconventional or non-proportional manner to provide a more userfriendly version of the figures. Reference to front, back, top andbottom are provided for exemplary purposes and are not limiting.

DETAILED DESCRIPTION

Certain embodiments are described below with reference to singular andplural terms in order to provide a user friendly description of thetechnology disclosed herein. These terms are used for conveniencepurposes only and are not intended to limit the materials and structuresdescribed herein as including or excluding certain features unlessotherwise noted as being present in a particular embodiment describedherein.

In certain configurations, the radomes described herein generallycomprise a substrate with a resin impregnated, added to or otherwisepresent in or on the substrate. The substrate may be produced bydisposing a plurality of individual plies or layers on each other andcoupling the plies together and/or molding or forming the plies to adesired shape to provide an article with desirable physical properties,e.g., to permit use of the article as a radome that may comprise one ormore of the following attributes: (1) a dielectric constant at 10 GHz(or other selected frequency, e.g., 1 MHz, 10 MHz, etc. as measured byASTM 2520 dated 2013) of less than or equal to 2.7, more particularly adielectric constant of less than or equal to 2.6, 2.5 or even 2.4, (2) awater absorption (as measured by ASTM D570-98) of less than or equal to1.5%, more particularly, less than or equal to 1.4%, 1.3%, 1.25%, 1.1%,1% or even less than or equal to 0.75% and/or (3) a glass transitiontemperature of at least 150° C., more particularly at least 175° C., asmeasured by ASTM D3418-03. In some embodiments, the radomes describedherein may comprise a loss tangent (as measured by ASTM 2520) of lessthan or equal 0.004, more particularly, less than or equal to 0.003,0.00275, 0.0025 or even less than or equal to 0.00225. Unless otherwisespecified, reference to dielectric constant and loss tangent in thedescription below and the claims appended hereto refer to valuesobtained using the ASTM 2520 test noted above. While described morespecifically in the ASTM 2520 protocol, the dielectric strength wasgenerally measured using cavity perturbation methods and a rectangularwaveguide. The sample is placed between plates of the waveguide tomeasure the dielectric properties. Similarly, reference to moisture orwater absorption values refer to those values obtained using ASTMD570-98. While described more specifically in the ASTM D570-98 protocol,the moisture absorption was generally measured by drying disk specimensin an oven for a specified time and temperature and then placing them ina desiccator to cool. Immediately upon cooling the specimens areweighed. The material is then emerged in water at a specifiedtemperature, e.g., 23° C. for 24 hours or until equilibrium. Specimensare removed, patted dry with a lint free cloth, and weighed to determinethe amount of water absorbed. Glass transition temperature may also bemeasured by suitable ASTM tests such as, for example, ASTM D3418-03. Theresins described herein are generally considered thermoset orthermosetting resins so the cured article can withstand environmentalconditions commonly encountered by radomes, though in certain instancesone or more thermoplastic materials may be present in certain areas,layers or parts of the articles.

In certain embodiments, the resins used herein to produce the radomesmay comprise an effective amount of monomer blended with an effectiveamount of an oligomer. For example, in some embodiments, the resin maycomprise a major amount of the monomer and a minor amount of theoligomer. The terms “major” and “minor” refer to the amount, by weight,of the monomer and oligomer. For example, where a monomer and anoligomer are present, a major amount of the monomer would be presentwhen the weight percentage of the monomer exceeds the weight percentageof the oligomer. In some instances, the monomer may be present in anamount that exceeds 50 weight percent based on the weight of the monomerand the oligomer. As noted below, by producing blends with effectiveamounts of a monomer and an oligomer, desirable properties can beachieved to render the resins suitable for use in radomes and othersimilar applications.

In certain examples, the monomer for use in the resin blends describedherein may not provide desirable properties when polymerized with itselfor with another monomer. For example, by itself the monomer may providea resin having a high dielectric constant or high water absorption, butwhen the monomer is combined with an oligomer and the mixture ispolymerized, the resulting resin provides desirable properties. In someinstances, the monomer used in the resin blends described herein may bea cyanate ester. In certain embodiments, the monomer may comprise acompound of formula (I)

where R¹ and R² are each independently selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl. R3 and R4 are eachindependently selected from hydrogen, methyl, phenyl, trifluoromethyl,ethyl, dichloroethylene, a hydrocarbon group comprising 1 to 6 carbonatoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms. In someinstances, one of R¹ and R² is —CN and the other group of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, and ahalohydrocarbonyl group comprising 1 to 6 carbon atoms, and R³ and R⁴are each independently hydrogen, methyl, phenyl or trifluoromethyl. Insome instances, each of R³ and R⁴ may be hydrogen or may be methyl ormay be phenyl. In certain embodiments, the monomer may comprise acompound of formula (II)

where R¹ and R² are each independently selected from independentlyselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹ and R² is —CN and the other groupis selected from independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl. In some instances, each of R¹ and R² of formula (II) is —CN.In other instances, the monomer used in the resin blends describedherein may comprise a compound of formula (III)

where R¹ and R² are each independently selected from independentlyselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹ and R² is —CN and the other groupis selected from independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl. In some instances, each of R¹ and R² of formula (III) is—CN. In other configurations, the monomer used in the resin blendsdescribed herein is a compound of formula (IV)

where R¹ and R² are each independently selected from independentlyselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹ and R² is —CN and the other groupis selected from independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl. In certain instances, each of R¹ and R² of formula (IV) is—CN. In other configurations, the monomer used in the resin blendsdescribed herein is a compound of formula (V)

where R¹ and R² are each independently selected from independentlyselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹ and R² is —CN and the other groupis selected from independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl. In certain instances, each of R¹ and R² of formula (V) is—CN. In other configurations, the monomer used in the resin blendsdescribed herein is a compound of formula (VI)

where R¹ and R² of formula (VI) are each independently selected fromindependently selected from hydrogen, —CN, —COOH, a hydrocarbon groupcomprising 1 to 6 carbon atoms, a hydrocarbonyl group comprising 1 to 6carbon atoms, a halohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹ and R² of formula (VI) is —CN andthe other group is selected from independently selected from hydrogen,—CN, —COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl. In certain instances, each ofR¹ and R² of formula (VI) is —CN. In other configurations, the monomerused in the resin blends described herein is a compound of formula (VII)

where R¹, R², R³ and R⁴ of formula (VII) are each independently selectedfrom hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to 6 carbonatoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹, R², R³ and R⁴ of formula (VII) is—CN and the other groups are independently selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl. In certain instances, each ofR¹ and R² of formula (VII) is —CN and R³ and R⁴ are each independentlyselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome instances, R³ and R⁴ are each independently phenyl or isopropyl. Inother embodiments, the monomer used in the resin blends described hereinis a compound of formula (VIII)

where R¹ and R² of formula (VIII) are each independently selected fromindependently selected from hydrogen, —CN, —COOH, a hydrocarbon groupcomprising 1 to 6 carbon atoms, a hydrocarbonyl group comprising 1 to 6carbon atoms, a halohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹ and R² of formula (VII) is —CN andthe other group is selected from independently selected from hydrogen,—CN, —COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl. In certain instances, each ofR¹ and R² of formula (VIII) is —CN. In other embodiments, the monomerused in the resin blends described herein is a compound of formula (IX)

where R¹, R², R³ and R⁴ of formula (IX) are each independently selectedfrom hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to 6 carbonatoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Insome embodiments, at least one of R¹, R², R³ and R⁴ of formula (IX) is—CN and the other groups are selected from independently selected fromhydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to 6 carbonatoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl. Incertain instances, each of R¹ and R² of formula (VII) is —CN and R³ andR⁴ are each independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl. In some instances, R³ and R⁴ are each independentlyhydrogen, methyl, ethyl, propyl or isopropyl.

In some embodiments, commercially available monomers suitable for use inthe resin blends described herein may include AroCy B-10 MonomericBisphenol-A Dicyanate, AroCy B-30 Prepolymer Bisphenol-A Dicyanate,AroCy B-40S Prepolymer Bisphenol-A Dicyanate, AroCy M-10 MonomericBisphenol F Dicyanate, AroCy M-20 Monomeric Bisphenol F Dicyanate andAroCy M-30 Bisphenol Dicyanate Prepolymer, each of which is commerciallyavailable from Huntsman (The Woodlands, Tex.). Other suitable monomersare commercially available, for example, from Cytec Industries (WoodlandPark, N.J.) and Sigma-Aldrich (St. Louis, Mo.). In some embodiments, theresin blends provided herein comprise a monomer of formula (I)-(IX)where at least one of the monomers of the resins comprises a cyanatogroup, e.g., —CN, cyanatophenyl, diphenylcyanate or other suitablecompounds with a —CN group. In other instances, the monomer may be oneor more materials commercially available from Lonza (Switzerland) suchas, for example, dicyclopentadienyl bisphenol cyanate ester. In someembodiments, the monomer may be a cyanate ester derivative ofnorbornene, dicyclopentadiene, 5-methyl-2-norbonene,5-ethyl-2-norbornene, 5-ethylene-2-norbornene, 5-propyl-2-norbonene,5-butyl-2-norbonene, 5-pentanyl-2-norbonene, 5-hexyl-2-norbonene,5-cyclohexyl-2-norbonene, 5-septyl-2-norbonene, 5-octyl-2-norbonene,5-nonyl-2-norbonene, 5-decyl-2-norbonene,5-ethylene-5-chloro-2-norbornene, 5-propyl-5-chloro-2-norbonene,5-butyl-5-chloro-2-norbonene, 5-pentanyl-5-chloro-2-norbonene,5-hexyl-5-chloro-2-norbonene, 5-cyclohexyl-5-chloro-2-norbonene,5-septyl-5-chloro-2-norbonene, 5-octyl-5-chloro-2-norbonene,5-nonyl-5-chloro-2-norbonene, 5-decyl-5-chloro-2-norbonene,5-methyl-5-bromo-2-norbornene, 5-ethylene-5-bromo-2-norbornene,5-propyl-5-bromo-2-norbonene, 5-butyl-5-bromo-2-norbonene,5-pentanyl-5-bromo-2-norbonene, 5-hexyl-5-bromo-2-norbonene,5-cyclohexyl-5-bromo-2-norbonene, 5-septyl-5-bromo-2-norbonene,5-octyl-5-bromo-2-norbonene, 5-nonyl-5-bromo-2-norbonene,5-decyl-5-bromo-2-norbonene, methyl 5-norbornene-2-carboxylate, ethyl5-norbornene-2-carboxylate, phenyl 5-norbornene-2-carboxylate, methyl2-methyl-5-norbornene-2-carboxylate, butyl3-phenyl-5-norbornene-2-carboxylate, dimethyl5-norbornene-2,3-dicarboxylate, cyclohexyl 5-norbornene-2-carboxylate,allyl 5-norbornene-2-carboxylate, 5-norbornene-2-yl acetate,5-norbornene-2-nitrile, 3-methyl-5-norbornene-2-nitrile,2,3-dimethyl-5-norbornene-2,3-dinitrile, 5-norbornene-2-carboxylic acidamide, N-methyl-5-norbornene-2-carboxylic acid amide,N,N-diethyl-5-norbornene-2-carboxylic acid amide,N,N,N′,N′-tetramethyl-5-norbornene-2,3-dicarboxylic acid diamide,5-chloro-2-norbornene, 5-bromo-2-norbornene, 5-fluoro-2-norbornene,5-methyl-5-chloro-2-norbornene, chloroethyl 5-norbornene-2-carboxylate,dibromopropyl 5-norbornene-2-carboxylate, dichloropropyl5-norbornene-2-carboxylate, monochlorophenyl 5-norbornene-2-carboxylate,monobromophenyl 5-norbornene-2-carboxylate, tribromophenyl5-norbornene-2-carboxylate, 2,3-dichloro-5-norbornene,2-bromo-5-norbornene, 2-bromomethyl-5-norbornene, tribromobenzyl5-norbornene-2-carboxylate, 5-norbornene-2,3-dicarboxylic anhydride,2,3-dimethyl-5-norbornene-2,3-dicarboxylic anhydride,5-norbornene-2,3-dicarboxylic acid imide,N-phenyl-2-methyl-5-norbornene-2,3-dicarboxylic acid imide,2-trichlorosilyl-5-norbornene, 2-(dimethylmethoxysilyl)-5-norbornene,2-(dimethylacetylsilyl)-5-norbornene, and 2-trimethylsilyl-5-norbornene.

In some embodiments, certain monomers described herein may bepolymerized to provide a suitable resin for use in a radome. Forexample, certain cyanato or dicyanato monomers can be polymerized in theabsence of an oligomer to provide a suitable resin, e.g., a resin with adielectric constant at 10 GHz (as measured by ASTM 2520) of less than orequal to 2.7, more particularly a dielectric constant of less than orequal to 2.6, 2.5 or even 2.4, (2) a water absorption (as measured byASTM D570-98) of less than or equal to 1.5%, more particularly, lessthan or equal to 1.4%, 1.3%, 1.25%, 1.1%, 1% or even less than or equalto 0.75% and/or (3) a glass transition temperature of at least 150° C.,more particularly at least 150° C., in particular at least 175° C., asmeasured by ASTM D3418-03. Any of the monomers of formula (I)-(IX) maybe polymerized in the absence of a monomer, and illustrative monomers offormula (I)-(IX) are those where one or both of R¹ and R² are —CN.

In certain embodiments, the monomers described herein may be combinedwith each other and with an oligomer to provide the resin blend. In someexamples, two or more monomers each of formulae (I)-(IX) (or the othermonomers described herein) may be combined with an oligomer. In someinstances, the monomers may have the same general formula, e.g., mayboth be a compounds of formula (I) but have different groups for atleast one of R¹ and R², whereas in other examples the two monomers mayhave a different formula, e.g., one monomer may be a compound of formula(I) and the other monomer may be a compound of formula (IX). Manydifferent combinations where two different monomers of formulae (I)-(IX)can be combined and will be selected by the person of ordinary skill inthe art, given the benefit of this disclosure.

In certain examples, the resins blends described herein also compriseone or more oligomers. In certain instances, one monomeric unit fromformulae (I)-(IX) and another monomeric unit of formula (I)-(IX) arepresent in the oligomer. If desired, the monomeric unit may be one ofthe other monomeric units described herein. In some instances, theoligomer may comprise at least one similar monomeric unit, whereas inother instances the oligomer may comprise all different monomeric units.In some embodiments, at least one monomeric unit of the oligomercomprises a —CN group. In certain embodiments, the oligomer comprisesthree or more monomeric units independently selected from monomericunits with formulae (I)-(IX). For example, the oligomer may comprisethree monomeric units of formula (I), three monomeric units of formula(II), three monomeric units of formula (III), etc. In some instances,two of the three monomeric units may be the same, whereas in otherinstances all three monomeric units of the oligomer may be different.While specific configurations of two and three monomeric unit oligomersare described herein, it will be recognized by the person of ordinaryskill in the art, given the benefit of this disclosure, that oligomerscomprising four, five, or six monomeric units may also be used.

In some instances and for illustration purposes only, the oligomer maycomprise a monomer having a general formula (II) as shown in formula (X)

where n is 2, 3, 4, 5 or 6 or higher than 6. In some embodiments, n is 2or 3. While a monomer of formula (II) is shown for illustration, any oneor more monomers with formulae (I)-(IX) may be present in the oligomer.In addition, the exact species bound to the monomeric unit will dependon the particular other reactants present in the resin blend.

In some examples, the resin blends may comprise two or more differentoligomers in combination with one or more monomers. For example, twodifferent oligomers may be combined with a single monomer and permittedto polymerize in the presence of a catalyst. In other instances, asingle oligomer may be combined with two different monomers andpermitted to polymerize in the presence of a catalyst. In certainexamples, the resin blend may be produced by first combining a firstoligomer and a first monomer during a first period to permitpolymerization and then adding a second, different monomer to themixture for a second period to permit polymerization. In otherinstances, the resin blend may be produced by first combining a firstoligomer, a second oligomer (different from the first) and a firstmonomer during a first period to permit polymerization and then adding asecond, different monomer to the mixture for a second period to permitpolymerization. In additional instances, the resin blend may be producedby first combining a first oligomer, a first monomer and a secondmonomer (different from the first) during a first period to permitpolymerization and then adding a second, different oligomer to themixture for a second period to permit polymerization.

In certain instances, the resin blends described herein may comprise aneffective amount of each of the monomer and the oligomer to provide aresin with desirable physical properties for use in radomes and othersimilar applications. For example, the resin blend may comprise (1) adielectric constant at 10 GHz (as measured by ASTM 2520) of less than orequal to 2.7, more particularly a dielectric constant of less than orequal to 2.6, 2.5 or even 2.4, (2) a water absorption (as measured byASTM D570-98) of less than or equal to 1.5%, more particularly, lessthan or equal to 1.4%, 1.3%, 1.25%, 1.1%, 1% or even less than or equalto 0.75% and/or (3) a glass transition temperature of at least 150° C.,more particularly at least 150° C., in particular at least 175° C., asmeasured by ASTM D3418-03. In some embodiments, the resin blendsdescribed herein may comprise a loss tangent (as measured by ASTM 2520)of less than or equal 0.004, more particularly, less than or equal to0.003, 0.00275, 0.0025 or even less than or equal to 0.00225. The resinsblends described herein are generally considered thermoset orthermosetting resins so the cured article can withstand environmentalconditions commonly encountered by radomes, though in certain instancesone or more thermoplastic materials may be present in certain areas,layers or parts of the articles. In some embodiments, the effectiveamount of the monomer, by weight percent, may generally exceed theeffective amount of the oligomer, by weight percent. For example, themonomer may be added to the resin blend in about 50-70 weight percentwith the balance of the blend comprising the oligomer, e.g., theoligomer may be present from about 30-50 weight percent. In otherinstances, the monomer may be present in about 60-90 weight percent andthe oligomer may be present from about 10-40 weight percent. In someembodiments where more than a single monomer is present, the combinedweight percentages of the monomer may be selected to exceed the weightpercentage of the oligomer. For example, the combined weight percentagesof the two monomers may be greater than 50 weight percent.

In certain instances, suitable oligomers can be obtained (or produced)from materials commercially available, for example, from CytecIndustries (Woodland Park, N.J.) and Sigma-Aldrich (St. Louis, Mo.). Insome embodiments, the resin blend comprises an oligomer of AroCy cyanateester such as, for example, AroCy XU 378, XU 71787.02L, XU 7187.07L orother comparable cyanate ester materials. In some instances, the resinblends provided herein comprise an oligomer where the oligomer comprisesone, two or three cyanato group, e.g., —CN, cyanatophenyl,diphenylcyanate or other suitable compounds with a —CN group.

In certain embodiments, the resin blends described herein may comprisetwo or more different resin blends. For example, a first resin blend canbe produced using a first monomer and a first oligomer and a secondresin blend can be produced using a second monomer and a secondoligomer. The different resin blends may be permitted to polymerize fora first period and then combined together to complete polymerization orcuring of the resin. In some instances, the first and second resin blendmay combined with each other and then disposed on a substrate asdescribed herein.

In some embodiments, the resin blends described herein can be used incombination with other materials. For example, one or more additionalmaterials may be present in the resins produced using the cyanate estersdescribed herein. Illustrative additional materials include, but are notlimited to, pigments, carbon black, natural rubber, silicone rubber,urethane rubber, a urethane, a polyurethane, polyvinyl chloride,polyvinylidene chloride, polyvinyl alcohol, and their copolymers withacrylic acid or acrylic acid esters or other vinyl ester monomers,fluoropolymers, including fluoroplastics (such as PTFE, FEP, TFA, ETFE,THV, etc.) and fluoroelastomers, some other polymeric material, orblends thereof. Where fluoropolymers are present, monomers ofchlorotrifluoroethylene (CTFE) and vinylidene fluoride (VF2), either ashomopolymers, or as copolymers with TFE, HFP, PPVE, PMVE and ethylene orpropylene can be used. Additionally, the fluoropolymer may comprise aperfluoropolymer such as homopolymers and copolymers oftetrafluoroethylene (TFE), hexafluoropropylene (HFP) and fluorovinylethers, including perfluoropropyl and perfluoromethyl vinyl ether.

In certain embodiments, one or more of the resins described above may beused along with a suitable substrate to provide a prepreg or curedarticle. While the exact properties of the resin, prepreg and curedarticle may differ, in some instances, the prepreg may include one ormore of the following physical properties (1) a dielectric constant at10 GHz MHz (as measured by ASTM 2520) of less than or equal to 2.7, moreparticularly a dielectric constant of less than or equal to 2.6, 2.5 oreven 2.4, (2) a loss tangent (as measured by ASTM 2520) of less than orequal 0.003, more particularly, less than or equal to 0.00275, 0.0025 oreven less than or equal to 0.00225, and (3) water absorption (asmeasured by ASTM D570-98) of less than or equal to 1.5%, moreparticularly, less than or equal to 1.4%, 1.3%, 1.25%, 1.1%, 1% or evenless than or equal to 0.75%. In other embodiments, the cured articledesirably comprises one or more of the following physical properties:(1) a dielectric constant at 10 GHz (as measured by ASTM 2520) of lessthan or equal to 2.7, more particularly a dielectric constant of lessthan or equal to 2.6, 2.5 or even 2.4, (2) a loss tangent (as measuredby ASTM 2520) of less than or equal 0.003, more particularly, less thanor equal to 0.00275, 0.0025 or even less than or equal to 0.00225, and(3) water absorption (as measured by ASTM D3418-03) of less than orequal to 1.5%, more particularly, less than or equal to 1.4%, 1.3%,1.25%, 1.1%, 1% or even less than or equal to 0.75%.

In certain embodiments and referring to FIG. 1, a prepreg 100 is shownthat comprises two plies 110 and 120. Each of the plies 110, 120 may bethe same or may be different. In some embodiments, at least one of theplies 110, 120 comprises one or more of the resins described herein. Forexample, one of the plies 110, 120 may include a resin blend, asdescribed herein, in a pre-polymerized form. A catalyst may be presentin combination with the resin blends if desired. The plies 110, 120 mayeach comprise yarns or fiber oriented in a desired manner as described,for example, in commonly assigned U.S. Pat. No. 7,153,792, the entiredisclosure of which is incorporated herein by reference. In preparingthe prepreg, the components of the resins described herein can be mixedor combined and the mixture can be coated onto, disposed into,impregnated with or otherwise added to each of the plies 110, 120, e.g.,each of the plies can be dipped into a solution or mixture comprisingthe resin blend. A catalyst may then be added to the plies. In otherinstances, the resin may first be formed and then added to the plies.For example, the resin may first be formed and each of the plies may bedipped into the resin to add the resin to the plies. Each of the plies110, 120 may be coupled to each other by disposing one ply on the otherply, and the resulting prepreg may be cured to provide a cured article.Examples of curing processes are described in more detail below. Priorto curing, the prepreg 100 may be shaped or formed into a desired shapewith a desired size, e.g., a dome shape effective to cover an antenna orcommunication structure. Illustrative shaping and forming methods aredescribed herein below.

In some configurations, the article may comprise three or more plieseach laid on each other and cured to provide the article. Referring toFIG. 2, a prepreg 200 comprising three plies 210, 220 and 230 is shown.The composition of the ply 220 is different from that of the plies 210and 230. For example, the resins of the three plies 210, 220 and 230 maybe the same, but the substrate present in ply 220 may be different. Inother instances, the substrates in the plies 210, 220 and 230 may be thesame, but the resin present in the ply 220 may be different. Inadditional configurations, the resin and the substrate in the ply 220may be different than that in the plies 210 and 230. In some instances,the resins and substrates present in each of the plies 210, 220 and 230may be the same, but the thickness of the substrates or the amount ofresin present may be different in one of the plies. Other configurationsusing three or more plies where one of the plies is physically orchemically different will be selected by the person of ordinary skill inthe art, given the benefit of this disclosure.

In certain instances, the prepregs may comprise one or more additionallayers or materials disposed on them. For example and referring to FIG.3, the prepreg 300 may comprise a protective covering 330 disposed on asurface of a first ply 310. The ply 310 is coupled to another ply 320.The protective covering 330 may take the form of a film, coating, alayer, a laminate or other suitable coverings that can act to protectthe layers underneath the covering 330. In some embodiments, thecovering may be designed to filter out wavelengths outside of a certainfrequency while permitting desirable wavelengths to pass through thestructure to an underlying antenna or electronic device. For example,the covering 330 may be configured as a low pass filter, a high passfilter or both to provide a transmission window permitting frequencieswithin the window to be transmitted through the prepreg 300. While asingle covering 330 is shown, two or more coverings, layers or the likemay be present. In addition, if desired, a covering may be disposed onthe ply 320 such that coverings sandwich the plies within the prepreg300. In some instances, the covering 330 may be selected for aestheticpurposes, e.g., may be camouflaged or selectively colored, but does nothave any protective or functional properties. In some embodiments, thecovering 330 may comprise a different material than present in theprepregs. For example, the covering may comprise ultra-high molecularweight polyethylene (UHMWPE) or fiber-reinforced UHMWPE. In otherinstances, the covering 330 may comprise polyetheretherketone (PEEK) orfiber-reinforced PEEK. Additional suitable covering materials differentfrom those present in the substrates of the prepregs will be selected bythe person of ordinary skill in the art, given the benefit of thisdisclosure.

In certain embodiments, many different substrates can be used to preparethe prepregs described herein. In some embodiments, the substrate isgenerally transparent to radio waves or microwaves (or another desiredradiation frequency) when present in the prepreg or cured article. Forexample, the substrate may pass radio signals or microwave signals sentfrom a transmitter within the structure formed by the substrate. Inaddition, the substrate may permit a receiver within the structureformed by the substrate to receive radio signals or microwave signalsreflected from an object or sent from a transmitter of another device orsystem. The cured articles are generally thin walled but structurallyrobust to withstand the various forces encountered by articles.

In certain examples, the substrates of the articles described herein maybe porous substrates that can be impregnated with a resin produced asdescribed herein. The substrates may be, or may comprise, a wovenfabric, a non-woven fabric, a ceramic, a plastic, a glass, a polymer, ormay take other forms. In some instances, the substrate may comprisefiberglass, nylon, polyester, a polyethersulfone, an aramid (such asKEVLAR® or NOMEX® available from Dupont), a polyethylene, apolypropylene, a polyolefin, a polyimide, a polyamide, apolyamide-imide, a polyphenylene sulfide, carbon, carbon black,graphite, diamond, a polybenzimidazole (PBI), a polybenzoxazole (PBO), ahalocarbon or other suitable materials. In some instances, the substratemay comprise one or more forms of glass. For example, the substrate maybe produced from E-glass (alumino-borosilicate glass with less thanabout 1 weight percent alkali oxides), A-glass (alkali-lime glass withsubstantially no boron oxide), E-CR-glass (alumino-lime silicate withless than 1% by weight alkali oxides), C-glass (alkali-lime glass withhigh boron oxide content), D-glass (borosilicate glass with a lowdielectric constant), L-glass (ultra-low dispersion glass commonly usedin optics), R-glass (alumino silicate glass without any substantialamounts of MgO and CaO), and S-glass (alumino silicate glass without CaObut with high MgO content).

In some instances, the substrate may be fiber free or may befiber-reinforced to provide additional strength. Where fibers arepresent, the fibers may be thermoplastic fibers, thermoset fibers, glassfibers, ceramic fibers, metal fibers or other suitable types of fibers.For example, one or more glass fibers selected from E-glass fibers,A-glass fibers, E-CR-glass fibers, C-glass fibers, D-glass fibers,R-glass fibers and S-glass fibers can be used in the substrate. Thesubstrate may include a first material, e.g., a fabric, and a seconddifferent material, e.g., glass fibers, if desired. The differentmaterials may be present as separate plies of a multi-ply prepreg or maybe present in regions or zones or the same ply. In some embodiments, thefibers may be added directly to the resins described herein, e.g., aresin of formulae (I)-(III), prior to addition of the resin to thesubstrate. In other instances, two or more different types of fibers arepresent in the substrate or the final article.

In certain embodiments, the substrates described herein and/or theresins described herein may comprise one or more additives. For example,the substrate may comprise crystals, quartz, glass particles,stabilizing agents, flame retardants (halogenated flame retardants,phosphorated flame retardants, etc.), smoke suppressants, or othermaterials to impart one or more desired physical properties to the curedarticle comprising the substrate. In certain examples, one or more metalcatalysts may be added to the resins. For example, a metal catalyst,e.g., a transition metal catalyst such as chromium acetylacetonate, maybe added to the resin. In some instances, one or more hardeners orcuring agents may be included in the substrate or resin or both toincrease (or decrease) the rate at which the prepregs cure to form thefinal article. When cured, the prepregs generally form a hard articlethat is inflexible. Such hard structures are desirably suitable forprotecting underlying electronic devices from damage from weather orunwanted physical contact. In other instances, however, the curedarticles may be flexible, at least to some degree, after curing or mayinclude flexible sections after curing. The flexible articles can bebent to at least some degree into a desired shape and may be held in thedesired shape using suitable fasteners, e.g., bolts, screws, adhesives,rivets or other suitable fasteners.

In some embodiments, the articles described herein may comprise one ormore additional layers coupled to the prepreg layers. For example, aporous, foam or honeycomb structure may be present between prepreglayers comprising the resins described herein to increase the overallthickness of the cured article without imparting too much weight.Alternatively, the foam may be present on an inner surface, e.g., nearan antenna or other electronic device, to increase the overall thicknessof the articles. Where such foams or other layers are present, thematerials selected for the other layers desirably do not alter thephysical properties of the final article, e.g., the final article stillcomprises one or more of (1) a dielectric constant at 10 GHz (asmeasured by ASTM 2520) of less than or equal to 2.7, more particularly adielectric constant of less than or equal to 2.6, 2.5 or even 2.4, (2) aloss tangent (as measured by ASTM 2520) of less than or equal 0.003,more particularly, less than or equal to 0.00275, 0.0025 or even lessthan or equal to 0.00225, and (3) water absorption (as measured by ASTMD570-98) of less than or equal to 1.5%, more particularly, less than orequal to 1.4%, 1.3%, 1.25%, 1.1%, 1% or even less than or equal to0.75%.

In some examples, the prepregs described herein may be cured using manydifferent suitable methods. For example, the prepregs may be subjectedto heat to polymerize the resin and harden the prepreg. The exact curingtemperature used will depend on the particular resin blend selected, butillustrative curing temperatures include, but are not limited to 80° C.to about 100° C. or about 150° C. to about 200° C. In some embodiments,the monomer and oligomer selected for use in the resin may provide abi-curable resin that is cured in two or more different temperaturesteps. Without wishing to be bound by any particular scientific theory,the polymerization products which result from bi-curing, e.g., curing attwo different temperatures, may not be the same as the products whichresult from curing at a single temperature for the cure period. In someinstances, the resin materials may be combined with a catalyst and firstcured at a temperature of about 70° C. to about 110° C. for a firstperiod. The resin may then be cured for a second period at a highertemperature, e.g., about 150-200° C. for a second period. If desired, athird curing temperature higher than the first and second may also beused. Once polymerization ceases or terminates, the resin desirablyprovides a dielectric constant of less than 2.7, a loss tangent of lessthan 0.003 and a moisture absorption of less than 1.5%. In someinstances, it may be desirable to include a rate limiting compound withthe resin to limit the degree of polymerization during the first curingtemperature. For example, phosphines such as triphenylphosphine or othersuitable rate limiters may be added to ensure that polymerization is notcomplete during the first curing temperature. In other instances, thebi-curing temperatures can be selected to provide a resin (or prepreg orfinal, cured article) whose glass transition temperature is greater thana comparable resin produced using a single curing step.

In certain examples, the prepregs described herein may be cured usingsuitable devices such as molding apparatus, vacuum bag devices or usingother suitable methods and devices. If desired, the curing may beperformed in a substantially inert environment devoid of oxygen or othergases or an inert gas, e.g., nitrogen, may be introduced into the curingapparatus if desired. In some instances, curing may simultaneously beaccompanied by forming of the prepreg into a desired shape for use in anarticle such as, for example, a radome. For example, where the prepregsare used to form a radome, the prepregs can be formed into pieces whichcan be coupled to each other to form a dome or truncated sphere. Eachindividual piece can be molded or formed into a desired size andthickness and then coupled to other pieces to provide the radomestructure. Referring to FIG. 4, a system 400 comprises a radome 402constructed and arranged to protect an antenna 404. The antenna 404 ismounted on a support structure 406 which may include a power source andelectronics (not shown) such as a controller or processor, if desired,or may be electrically coupled to a controller or processor positionedbelow the structure 406. In use of the system 400, the antenna 404 iscovered by the radome 402 which is also supported on support structure406. The antenna 404 could alternately be located on a building, couldbe ground-based, could be coupled to an aircraft, recreational vehicle,train, bus, subway, automotive vehicle or other devices which maythemselves be mobile. The radome 402 comprises a suitable structureformed using one or more of the resins described herein to protect theantenna 404 from environmental elements without causing significantinterference to the signals to be transmitted and received by theantenna 404. For example, the radome 402 may be produced using one ormore prepregs or plies comprising one or more of the resins describedherein to provide a final radome structure that has a dielectricconstant at 10 GHz (as measured by ASTM 2520) of less than or equal to2.7, more particularly a dielectric constant of less than or equal to2.6, 2.5 or even 2.4. In some instances, the radome 402 may also have aloss tangent (as measured by ASTM 2520) of less than or equal 0.003,more particularly, less than or equal to 0.00275, 0.0025 or even lessthan or equal to 0.00225. In further configurations, the radome 402 mayalso have a water absorption (as measured by ASTM D570-98) of less thanor equal to 1.5%, more particularly, less than or equal to 1.4%, 1.3%,1.25%, 1.1%, 1% or even less than or equal to 0.75%. In someembodiments, the radome 402 is produced by coupling a plurality of pliesto each other, where least one of the plurality of plies comprises asubstrate and a resin as described herein.

In certain embodiments, while an antenna within a dish is shown underthe radome 402 in FIG. 4, the antenna may be part of a larger system orother electronic devices may instead be present under radomes. Forexample, the antenna 404 may be a high frequency radar antenna. In otherinstances, the antenna 404 may be a phased array or a dish (such as aparabolic dish, a split cylinder dish) and may be rotating ornon-rotating. In some instances, the antenna 404 and radomes 402 may bepart of a number of different types of radar system assemblies. Forexample, radome 402 can be used in conjunction with weather radarsystems, and airport radar systems. In certain examples, instead ofusing a radar antenna, the system 400 could include other antennas 404,one such antenna being a satellite communication antenna. In otherinstances, the radome 404 may be used as part of a cellularcommunication system to protect underlying antennas from weather. Insome embodiments, the radome may be part of a wireless communicationdevice, e.g., an outside Wi-Fi or Bluetooth system, that can providecommunication between devices. For example, the radome and Wi-Fi devicemay be part of a mobile communication system that permits users toaccess broadband communications devices through mobile devices such ascellular phones, laptops, tablets, etc. The Wi-Fi device/radome systemmay be mounted on a mobile vehicle or a non-mobile structure, e.g., atelephone pole, wall of a building, etc. In some embodiments, thecommunications system may comprise a first system configured to operateas a radar system and a second system configured to provide wirelessaccess. For example, a single radome of an aircraft or ship may house aradar system and a Wi-Fi system to permit user's on the aircraft or shipto have wireless communication through the mobile devices and the Wi-Fisystem.

In some examples, the radomes may be present on a vehicle such as anautomotive vehicle, truck, bus, train, subway, plane, a ship, asubmarine or the like. For example, the radome may be integrated into(or attached to) a front or rear bumper (or both) of a vehicle andprotect an underlying antenna that may transmit and receive waves forproximity detection. In other instances, the radome may be part of thevehicle to send and receive communications from and to the vehicle,e.g., may be part of a cellular communication network or wirelesscommunication system such as those found on ships, planes and trains.Where the radome is part of a ship, plane or train, it may take anaerodynamic shape to not increase drag to a substantial degree. Wherethe radome is present in underwater applications, e.g., on a submarinefor protecting a sonar system or in an underwater communication system,the radome may be sealed to a permanent structure so a fluid tight sealis present between the radome and the structure to protect anyunderlying antenna or other communications devices. Where thecommunication devices are deployed, e.g., from a submerged vessel to asurface, the radome may be buoyant to permit it to float on the surfacewithout the need for an external bladder or other flotation device. Thelow moisture absorption of the radomes described herein permit use ofthe radomes in salt water and other moist environments without anysubstantial interference of the transmission to and from electronicdevices within the radome.

In certain embodiments, the radomes described herein may be integral toan electronic device to protect the electronic device while at the sametime permitting the electronic device to receive and/or send signals.For example, a cellular phone may comprise an integral radome with anembedded microantenna. If desired, the microantenna can be configured torotate or move to increase the overall signal receiving capabilities ofthe phone. A touch screen can be electrically or wirelessly coupled tothe cellular phone to permit the user to access the phones features. Insome embodiments, the radome may be integral to a structural componentof a vehicle, e.g., a bumper, emergency lights, nose cone or othercomponents of vehicles such that the radome takes the general shape ofthe structural part of the vehicle.

In some embodiments, the radomes described herein may be used formilitary operations communications or emergency operationscommunications. For example, military personnel, police vehicles,emergency centers and the like may wish to use dedicated radio bandsoutside normal over the air scanning frequencies to communicate witheach other. A conventional handheld scanner may scan frequencies fromabout 29 MHz to about 1.3 GHz. These frequencies are generally referredto as very high frequencies (VHF) for frequencies from 30 MHz to about330 MHz or ultra-high frequencies (UHF) for frequencies from about 330MHz to about 2.9 GHz. While the radomes described herein can be used inVHF and UHF bands, emergency operation communications transmitted atthese frequencies may be received and heard by anyone with a hand heldscanner. To avoid reception by the public, the radomes described hereincan be used in combination with a transmitter/receiver to transmit orreceive signals in the S band (2-4 GHz), C band (4-8 GHz), X band (8-12GHz), K_(a) band (12-18 GHz), K band (18-26.5 GHz), K_(a) band (26.5-40GHz), Q band (30-50 GHz), U band (40-60 GHz), V band (50-75 GHz), E band(60-90 GHz), W band (75-110 GHz), F band (90-140 GHz) or D band (110-170GHz). In particular, bands such as the K_(a) band and Q band can be usedin satellite communications. For example, a satellite may include aradome and underlying transmitter/receiver configured totransmit/receive signals in the 20-50 GHz range. In addition,frequencies of 20-50 GHz may be used in nose cone radar systems (orradar systems positioned other than in the nose) of aircraft forclose-range targeting of targets. If desired, the geometry of the radomeon aircraft may be constructed to provide stealth like capability, e.g.,the radome does not comprise a shape at any portion that would readilyreflect radar waves and permit detection of the aircraft by enemypersonnel. The satellites may take the form of communication satellites,e.g., those with geostationary orbits, elliptical orbits or otherorbits, or other types of satellites or similar devices, e.g., weathersatellites, military satellites, astronomical satellites, navigationalsatellites, reconnaissance satellites, earth observation satellites, onspace stations or other devices that orbit the earth. In otherinstances, the resins and articles described herein can be used to coversonar systems, e.g., those used by the Navy that typically are designedto detect low frequencies in the 100-500 Hz or 1 kHz-10 kHz range. Thesonar systems may be fixed, e.g., positioned on the ocean floor, or maybe part of a vessel such as a ship or submarine.

In certain examples and referring to FIG. 5, a side view of a radome 510covering an electronic device 550 is shown. The radome 510 comprises aplurality of plies 515 as described herein. The radome may comprise aninner insulation layer 520, if desired, to insulate the electronicdevice 550 from the elements or to prevent thermal loss from inside theradome where an air conditioner (not shown) provides cooled air to anyelectronic devices within the radome 510. The radome 510 may alsocomprise structural support elements 525 integrally connecting sectionsof the radome 510. While the exact thickness of the radome 510 may varydepending on the intended use of the radome 510, in some instances, thethickness is about 0.01 inches thick to about 0.5 inches thick, moreparticularly about 0.01 inches to about 0.2 inches, for example, about0.07 inches to about 0.15 inches. The electronic device 550 may takemany forms as described herein and may include an antenna ortransmitter/receiver that can send and receive signals. In someembodiments, the electronic device 550 may be part of a radar system, asonar system, a communications system, e.g., Wi-Fi systems, Bluetoothsystems, radio systems, cellular communication systems, satellitesystems or other suitable systems.

In some embodiments, the prepregs and resins described herein may beused to construct thin-plate radomes. While the exact configuration mayvary, a thin plate radome is thin in comparison with the wavelength atthe operating frequency. In other instances, the radome may beconstructed as a half-wavelength radome, where the radome has athickness equivalent of about one-half the wavelength. Other variationssuch as quarter-wavelength radomes and the like may also be producedusing the materials and prepregs described herein.

The following paragraphs numerically numbered from 1 through 95 providefor various embodiments described herein.

1. A radome comprising a plurality of plies coupled to each other, inwhich at least one of the plurality of plies comprises a substrate and acured resin blend produced from an effective amount of a cyanate monomerand an effective amount of a cyanate ester oligomer to provide adielectric constant of less than 2.7, a glass transition temperature ofat least 150° C., in particular at least 175° C. and a moistureabsorption of less than 1.5% for the radome.

2. The radome of paragraph 1, in which the monomer is a compound offormula (I)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl, andwherein R³ and R⁴ are independently selected from hydrogen, —CN, —COOH,a hydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonylgroup comprising 1 to 6 carbon atoms, a halohydrocarbon group comprising1 to 6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbonatoms and phenyl.

3. The radome of paragraph 1, in which the monomer is a compound offormula (II)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

4. The radome of paragraph 1, in which the monomer is a compound offormula (III)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

5. The radome of paragraph 1, in which the monomer is a compound offormula (IV)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

6. The radome of paragraph 1, in which the monomer is a compound offormula (V)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

7. The radome of paragraph 1, in which the monomer is a compound offormula (VI)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

8. The radome of paragraph 1, in which the monomer is a compound offormula (VII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl, andwherein R³ and R⁴ are independently selected from hydrogen, —CN, —COOH,a hydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonylgroup comprising 1 to 6 carbon atoms, a halohydrocarbon group comprising1 to 6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbonatoms and phenyl.

9. The radome of paragraph 1, in which the monomer is a compound offormula (VIII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

10. The radome of paragraph 1, in which the monomer is a compound offormula (IX)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl,wherein R³ and R⁴ are each independently selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl.

11. The radome of any of paragraphs 1-10, in which the oligomer is acyanate ester oligomer comprising two or more monomeric units eachselected from a compound having the formula (I)-(IX).

12. The radome of paragraph 1, in which the cyanate monomer comprises abisphenol dicyanate group and the cyanate ester oligomer comprises adiphenylcyanate group.

13. The radome of paragraph 1, in which the monomer is present fromabout 30-70 weight percent.

14. The radome of paragraph 13, in which the oligomer is present fromabout 70-30 weight percent.

15. The radome of paragraph 1, further comprising at least one phenoladded to the resin blend.

16. The radome of paragraph 15, further comprising at least one metalcatalyst added to the resin.

17. The radome of paragraph 1, in which the substrate comprises one ormore of a woven fabric, a non-woven fabric, a ceramic, a plastic, aglass, a fiberglass, a nylon, a polyester, a polyethersulfone, anaramid, a polyethylene, a polypropylene, a polyolefin, a polyimide, apolyamide, a polyamide-imide, a polyphenylene sulfide, a carbon, acarbon black, a graphite, a diamond, a polybenzimidazole, apolybenzoxazole or a halocarbon.

18. The radome of paragraph 1, in which the effective amount of themonomer by weight exceeds the effective amount of the oligomer byweight.

19. The radome of paragraph 1, in which the radome further comprises aloss tangent of less than 0.004.

20. The radome of paragraph 1, further comprising an insulation materialdisposed on the inner surface of the radome.

21. A prepreg comprising a plurality of plies coupled to each other, inwhich at least one of the plurality of plies comprises a substrate and aresin blend comprising an effective amount of a cyanate monomer and aneffective amount of a cyanate ester oligomer to provide a cured resincomprising a dielectric constant of less than 2.7, a glass transitiontemperature of at least 150° C., in particular at least 175° C. and amoisture absorption of less than 1.5%.

22. The prepreg of paragraph 21, in which the monomer is a compound offormula (I)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

23. The prepreg of paragraph 21, in which the monomer is a compound offormula (II)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

24. The prepreg of paragraph 21, in which the monomer is a compound offormula (III)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

25. The prepreg of paragraph 21, in which the monomer is a compound offormula (IV)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

26. The prepreg of paragraph 21, in which the monomer is a compound offormula (V)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

27. The prepreg of paragraph 21, in which the monomer is a compound offormula (VI)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

28. The prepreg of paragraph 21, in which the monomer is a compound offormula (VII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl, andwherein R3 and R4 are independently selected from hydrogen, —CN, —COOH,a hydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonylgroup comprising 1 to 6 carbon atoms, a halohydrocarbon group comprising1 to 6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbonatoms and phenyl.

29. The prepreg of paragraph 21, in which the monomer is a compound offormula (VIII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

30. The prepreg of paragraph 21, in which the monomer is a compound offormula (IX)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl,wherein R³ and R⁴ are each independently selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl.

31. The prepreg of any of paragraphs 21-30, in which the oligomer is acyanate ester oligomer comprising two or more monomeric units eachselected from a compound having the formula (I)-(IX).

32. The prepreg of paragraph 21, in which the cyanate monomer comprisesa bisphenol dicyanate group and the cyanate ester oligomer comprises adiphenylcyanate group.

33. The prepreg of paragraph 21, in which the monomer is present fromabout 30-70 weight percent.

34. The prepreg of paragraph 33, in which the oligomer is present fromabout 70-30 weight percent.

35. The prepreg of paragraph 21, further comprising at least one phenoladded to the resin blend.

36. The prepreg of paragraph 35, further comprising at least one metalcatalyst added to the resin blend.

37. The prepreg of paragraph 21, in which the substrate comprises one ormore of a woven fabric, a non-woven fabric, a ceramic, a plastic, aglass, a fiberglass, a nylon, a polyester, a polyethersulfone, anaramid, a polyethylene, a polypropylene, a polyolefin, a polyimide, apolyamide, a polyamide-imide, a polyphenylene sulfide, a carbon, acarbon black, a graphite, a diamond, a polybenzimidazole, apolybenzoxazole or a halocarbon.

38. The prepreg of paragraph 21, in which the effective amount of themonomer by weight exceeds the effective amount of the oligomer byweight.

39. The prepreg of paragraph 21, in which the prepreg further comprisesa loss tangent of less than 0.004.

40. The prepreg of paragraph 21, further comprising a covering coupledto at least one of the plies of the prepreg.

41. A resin blend comprising an effective amount of a cyanate estermonomer and an effective amount of a cyanate ester oligomer to provide acured resin comprising a dielectric constant of less than 2.7, a losstangent of less than 0.004, a glass transition temperature of at least150° C., in particular at least 175° C. and a moisture absorption ofless than 1.5%.

42. The resin of paragraph 41, in which the monomer is a compound offormula (I)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

43. The resin of paragraph 41, in which the monomer is a compound offormula (II)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

44. The resin of paragraph 41, in which the monomer is a compound offormula (III)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

45. The resin of paragraph 41, in which the monomer is a compound offormula (IV)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

46. The resin of paragraph 41, in which the monomer is a compound offormula (V)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

47. The resin of paragraph 41, in which the monomer is a compound offormula (VI)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

48. The resin of paragraph 41, in which the monomer is a compound offormula (VII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl, andwherein R3 and R4 are independently selected from hydrogen, —CN, —COOH,a hydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonylgroup comprising 1 to 6 carbon atoms, a halohydrocarbon group comprising1 to 6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbonatoms and phenyl.

49. The resin of paragraph 41, in which the monomer is a compound offormula (VIII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

50. The resin of paragraph 41, in which the monomer is a compound offormula (IX)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl,wherein R³ and R⁴ are each independently selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl.

51. A resin blend comprising an effective amount of at least two cyanatemonomers and an effective amount of a cyanate ester oligomer to providea cured resin comprising a dielectric constant of less than 2.7, a losstangent of less than 0.004, a glass transition temperature of at least150° C., in particular at least 175° C. and a moisture absorption ofless than 1.5%.

52. The resin of paragraph 51, in which at least one of the monomers isa compound of formula (I)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

53. The resin of paragraph 51, in which at least one monomer is acompound of formula (II)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

54. The resin of paragraph 51, in which at least one monomer is acompound of formula (III)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

55. The resin of paragraph 51, in which at least one monomer is acompound of formula (IV)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

56. The resin of paragraph 51, in which at least one monomer is acompound of formula (V)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

57. The resin of paragraph 51, in which at least one monomer is acompound of formula (VI)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

58. The resin of paragraph 51, in which at least one monomer is acompound of formula (VII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl, andwherein R3 and R4 are independently selected from hydrogen, —CN, —COOH,a hydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonylgroup comprising 1 to 6 carbon atoms, a halohydrocarbon group comprising1 to 6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbonatoms and phenyl.

59. The resin of paragraph 51, in which at least one monomer is acompound of formula (VIII)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl.

60. The resin of paragraph 51, in which at least one monomer is acompound of formula (IX)

wherein at least one of R¹ and R² is —CN and the other of R¹ and R² isselected from hydrogen, —CN, —COOH, a hydrocarbon group comprising 1 to6 carbon atoms, a hydrocarbonyl group comprising 1 to 6 carbon atoms, ahalohydrocarbon group comprising 1 to 6 carbon atoms, ahalohydrocarbonyl group comprising 1 to 6 carbon atoms and phenyl, andwherein R³ and R⁴ are each independently selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl.

61. A system comprising:

the radome of any of paragraphs 1-20; and

an electronic device covered by the radome.

62. The system of paragraph 61, in which the electronic device comprisesan antenna.

63. The system of paragraph 61, in which the radome is sized andarranged to be placed on an aircraft.

64. The system of paragraph 61, in which the radome is sized andarranged to be placed on a ship.

65. The system of paragraph 61, in which the radome is sized andarranged to be placed on a hull of a ship, in which the radome isimmersed in the water during operation of the ship.

66. The system of paragraph 61, in which the electronic device is partof a radar system.

67. The system of paragraph 61, in which the electronic device is partof a sonar system.

68. The system of paragraph 61, in which the electronic device is partof a communication system.

69. The system of paragraph 68, in which the communication system isselected from the group consisting of Wi-Fi systems, Bluetooth systems,radio systems, cellular communication systems and satellite systems.

70. A satellite comprising a transmitter/receiver and the radome of anyof paragraphs 1-20 sized and arranged to protect thetransmitter/receiver.

71. An automotive vehicle comprising a transmitter/receiver configuredto couple to a bumper of the vehicle, the vehicle further comprises theradome of any of paragraphs 1-20 sized and arranged to protect thecoupled transmitter/receiver.

72. An aircraft comprising a radar system and the radome of any ofparagraphs 1-20 configured to cover and protect the radar system.

73. The aircraft of paragraph 72, in which the radar system ispositioned in a nose cone or an undersurface of the aircraft.

74. A ship comprising a radar system and the radome of any of paragraphs1-20 configured to cover and protect the radar system.

75. The ship of paragraph 74, in which the radar system is positionedexternal to the hull of the ship and beneath the water surface inoperation of the ship.

76. A submarine comprising a sonar system and the radome of any ofparagraphs 1-20 configured to cover and protect the sonar system.

77. The submarine of paragraph 76, in which the sonar system ispositioned external to the hull of the submarine.

78. A method of producing a radome comprising:

disposing the resin blend of any of paragraphs 41-60 on a substrate; and

polymerizing the disposed resin to provide a radome comprising adielectric constant of less than 2.7, a glass transition temperature ofat least 150° C., in particular at least 175° C. and a moistureabsorption of less than 1.5%.

79. The method of paragraph 78, in which polymerizing the disposed resinalso provided a radome with a loss tangent of less than 0.004.

80. The method of paragraph 78, further comprising adding at least oneadditive to the resin before or after polymerization of the resin.

81. The method of paragraph 80, in which the additive is a flameretardant, a smoke suppressant or a pigment.

82. The radome of any of paragraphs 1-20, further comprising one or moreof a flame retardant, a filler and a curing agent.

83. The prepreg of any of paragraphs 21-40, further comprising one ormore of a flame retardant, a filler and a curing agent.

84. The resin of any of paragraphs 41-60, further comprising one or moreof a flame retardant, a filler and a curing agent.

85. The radome of 1, in which the monomer is a dicyclopentadienylbisphenol cyanate ester.

86. The prepreg of paragraph 21, in which the monomer is adicyclopentadienyl bisphenol cyanate ester.

87. The resin of paragraph 41 or paragraph 51, in which the monomer is adicyclopentadienyl bisphenol cyanate ester.

88. The radome of paragraph 1 or the prepreg of paragraph 21, in whichthe oligomer comprises a dicyclopentadienyl bisphenol cyanate estermonomeric unit.

89. The resin of paragraph 41 or paragraph 51, in which the oligomercomprises a dicyclopentadienyl bisphenol cyanate ester monomeric unit.

90. A radome comprising a plurality of plies coupled to each other, inwhich at least one of the plurality of plies comprises a substrate and acured resin produced from an effective amount of a cyanate monomerselected from monomers of formula (I)-(IX) and dicyclopentadienylbisphenol cyanate ester monomers to provide a dielectric constant ofless than 2.7, a glass transition temperature of at least 150° C. and amoisture absorption of less than 1.5% for the radome.

91. A prepreg comprising a plurality of plies coupled to each other, inwhich at least one of the plurality of plies comprises a substrate and aresin comprising an effective amount of a cyanate monomer selected frommonomers of formula (I)-(IX) and dicyclopentadienyl bisphenol cyanateester monomers to provide a cured resin comprising a dielectric constantof less than 2.7, a glass transition temperature of at least 150° C. anda moisture absorption of less than 1.5%.

92. A resin comprising an effective amount of a cyanate ester monomerselected from monomers of formula (I)-(IX) and dicyclopentadienylbisphenol cyanate ester monomers to provide a cured resin comprising adielectric constant of less than 2.7, a loss tangent of less than 0.004,a glass transition temperature of at least 150° C. and a moistureabsorption of less than 1.5%.

93. The radome of paragraph 90 or the prepreg of paragraph 91 or theresin of paragraph 92, further comprising at least one phenol added tothe resin.

94. The radome of paragraph 90 or the prepreg of paragraph 91 or theresin of paragraph 92, further comprising at least one metal catalystadded to the resin.

95. The radome of paragraph 90 or the prepreg of paragraph 91, in whichthe substrate comprises one or more of a woven fabric, a non-wovenfabric, a ceramic, a plastic, a glass, a fiberglass, a nylon, apolyester, a polyethersulfone, an aramid, a polyethylene, apolypropylene, a polyolefin, a polyimide, a polyamide, apolyamide-imide, a polyphenylene sulfide, a carbon, a carbon black, agraphite, a diamond, a polybenzimidazole, a polybenzoxazole or ahalocarbon.

Certain specific examples were described below to illustrate some of thenovel aspects and features of the technology described herein.

Materials Used in the Examples

Cyanate ester materials that were used were obtained commercially fromHuntsman and Lonza; 2,2-bis(4-cyanatophenyl)propane (commercial name:Arocy B 10 from Huntsman),4,4′-(1,3-phenylenediisopropylidene)diphenylcyanate (commercial name:Arocy XU 366 from Huntsman), oligomer of4,4′-(1,3-phenylenediisopropylidene)diphenylcyanate (commercial name:Arocy XU 378 from Huntsman); ethylidene bis-4,1-phenylene dicyanate(commercial name: Arocy L-10 from Huntsman); Arocy XU 371 (commercialname from Huntsman); polyphenolcyanates (Primaset BA-3000; PrimasetDT-4000; Primaset DT-7000 commercial names from Lonza). Nonylphenol andchromium acetylacetonate were purchased from Sigma-Aldrich.Thermoplastics, such as noryl SA9000 and noryl SA120, are purchased fromSabic and fatty acid amides as a slip agent, such as Crodamide ER, waspurchased from Crodamide. Quartz 4581 fabric was purchased from JPS.

Examples 1-5

Examples 1-5 in Table 1 show various resin blend formulations that wereproduced using AroCy XU-378 (oligomer) and AroCy B-10 (monomer). Toprepare the blends, a mixture of Arocy XU-366 and Arocy B-10 (totalweight: 50 g) were placed in a 4 ounce glass jar, and the mixture wasstirred at 100° C. for 30 min. Next, a solution of chromiumacetylacetonate (75 mg; 0.15%) dissolved in nonylphenol (3.0 g; 6%) wasadded to the mixture, and then the mixture was stirred at the sametemperature for 3 minutes. The resin blend was poured into a preheateddisc shaped mold (2.5 inch diameter by ⅛ inch thickness) and then placedin a vacuum oven which was degased for 30 min at 100° C. under vacuum.Then, the blend was cured at 177° C. for 2 hours followed by post-curingat 200° C. for 1 hour. Table 1 shows the formulation, and the physicalproperties measured for each formulation.

TABLE 1 Formulation No. 1 2 3 4 5 Components AroCy XU-378 (oligomer) 10070 50 30 0 AroCy B-10 (monomer) 0 30 50 70 100 Nonylphenol 6 6 6 6 6Chromium acetylacetonate 0.15 0.15 0.15 0.15 0.15 Properties DielectricConstant (1 MHz) 2.57 2.67 2.60 2.59 2.8 Dielectric Constant (10 GHz)2.666 2.765 2.805 Loss Tangent (10 GHz) 0.00344 0.00529 0.00615 MoistureAbsorption (%) 0.29 0.55 T_(g) (° C.) 171.5 203.5 212.7 232.9 252.1The percentage moisture absorption was measured at 85° C./85% relativehumidity after 12 days.

As shown in Table 1, the resin blend formulations (Examples 2-4)exhibited a dielectric constant at 1 MHz of less than 2.7. Inparticular, where the monomer and the oligomer were each present from30-70 weight percent, suitable dielectric constants were obtained.Example 1 included only oligomer and no monomer and did not provide asuitable glass transition temperature, e.g., a T_(g) above 150° C., inparticular at least 175° C. Example 5 included no oligomer and a singlemonomeric cyanate compound (2,2-bis(4-cyanatophenyl)propane) andprovided a dielectric constant at 1 MHz above 2.7. By polymerizing theoligomer of formula 1 and monomeric compound of formula 5, a resin wasobtained that did not provide suitable properties for use in radomes.The results were consistent with a resin blend of a monomer and anoligomer providing a dielectric constant at 1 MHZ below 2.7.

The glass transition temperature T_(g) was also measured for all theexamples. The blend formulations (Examples 2-4) provided glasstransition temperatures above a threshold value, e.g., above about 150degrees Celsius.

Examples 6-9

Examples 6-9 show resin blends produced using AroCy XU-378 (oligomer)and AroCy XU-366 (monomer). Experimental procedures were same asdescribed in reference to Examples 1-5. Table 2 shows the formulationsand properties.

TABLE 2 Formulation No. 6 7 8 9 Components AroCy XU-378 100 70 30 0(oligomer) AroCy XU-366 0 30 70 100 (monomer) Nonylphenol 6 6 6 6Chromium 0.15 0.15 0.15 0.15 acetylacetonate Properties Dielectricconstant 2.57 2.56 2.57 2.44 (1 MHz) Dielectric Constant 2.666 2.6662.693 (10 GHz) Loss Tangent (10 GHz) 0.00344 0.00361 0.00369 MoistureAbsorption 0.29 0.32 0.31 (%) T_(g) (° C.) 171.5 174.2 177.0 177.4As shown in Table 2, the resin blend formulations (Examples 7 and 8)provided dielectric constants at 1 MHz of less than 2.7. The losstangent of one of the blends (Example 7) was measured and within anacceptable range, e.g., about 0.004 or below. The glass transitiontemperature of the blends was within an acceptable range, e.g., about150-240 degrees Celsius or above a threshold range of about 150° C., inparticular at least 175° C.

Laminate: The formulation of Example #9 was applied to a quartz fabric(JPS Quartz 4581 with a resin content of 35 weight percent) to provide aprepreg. A twelve-ply laminate (6 inches by 6 inches) was produced withthis prepreg and cured in a vacuum bag using following curingconditions: 177° C. for 2 hours; 200° C. for 1 hour. The dielectricconstant (10 GHz) of the laminate was measured to be 2.417, and the losstangent (10 GHz) was measured to be 0.0014, which is consistent with alaminate being produced that has a dielectric constant less than 2.7,and a loss tangent of less than 0.003. The results were consistent witha monomer comprising two cyanato groups providing a resin with desiredproperties.

Examples 10-14

Examples 10-14 were produced using AroCy XU-366 (monomer) and AroCy B-10(monomer). Experimental procedures were the same as described inExamples 1-5. Table 3 shows the formulation and properties.

TABLE 3 Formulation No. 10 11 12 13 14 Components AroCy XU-366 (monomer)100 70 50 30 0 AroCy B-10 (monomer) 0 30 50 70 100 Nonylphenol 6 6 6 6 6Chromium acetylacetonate 0.15 0.15 0.15 0.15 0.15 Properties DielectricConstant (1 MHz) 2.44 2.59 2.57 2.78 2.8 Dielectric Constant (10 GHz)2.693 2.735 2.715 Loss Tangent (10 GHz) 0.00359 0.00435 0.00661 MoistureAbsorption (%) 0.31 0.56 T_(g) (° C.) 177.4 201.4 212.0 238.7 252.1Two of the monomer blend formulations (Examples 11 and 12) using 50% orless of the monomer AroCy B-10 provided dielectric constants at 1 MHz ofless than 2.7. The glass transition temperature of Examples 11 and 12were within an acceptable range, e.g., 175-240 degrees Celsius. Themoisture absorption of Example 11 was also minimal. The resins producedusing a single monomer (Formulations 10 and 14) did not provide asuitable loss tangent, e.g., less than 0.003, for use in radomes.

Examples 15-19

Examples 15-19 show polymers produced using AroCy L-10 (monomer) andAroCy B-10 (monomer). Experimental procedures were the same as describedin Examples 1-5. Table 4 shows the formulation and properties.

TABLE 4 Formulation No. 15 16 17 18 19 Components AroCy L-10 (monomer)100 70 50 30 0 AroCy B-10 (monomer) 0 30 50 70 100 Nonylphenol 6 6 6 6 6Chromium acetylacetonate 0.15 0.15 0.15 0.15 0.15 Properties Dielectricconstant (1 MHz) 2.76 2.69 2.69 2.72 2.80When using blends of certain monomers, the dielectric constant at 1 MHzis about 2.7 or higher. These results are consistent with certainmonomer blends not providing resins with desirable physical properties.

Examples 20-22

Examples 20-22 show polymers made using three components, AroCy XU-366(monomer)/XU-378 (oligomer)/B-10 (monomer). Experimental procedures weresame as described in examples 1-5. Table 5 shows the formulation andproperties.

TABLE 5 Formulation No 20 21 22 Components AroCy XU-366 (monomer) 40 3030 AroCy XU-378 (oligomer) 30 30 20 AroCy B-10 (monomer) 30 40 50Nonylphenol 6 6 6 Chromium acetylacetonate 0.15 0.15 0.15 PropertiesDielectric constant (1 MHz) 2.60 2.69 2.72The dielectric constant of formula 20, which included a majority byweight (40% by weight) of AroCy XU-366(4,4′-(1,3-phenylenediisopropylidene)diphenylcyanate) monomer was lowerthan the other two formulations.

Examples 22-25 show polymers made using AroCy XU-366, thermoplastics,such as polyphenyleneoxide (PPO), and some other additives. Prepreg wasmade using quartz 4581 fabric and the resin content was ca. 40 wt. %. Atwelve-ply laminate (6″×6″) with zero direction was laid up with theprepreg and cured in a vacuum bag using following curing condition: 177°C. for 2 h followed by post-curing at 200° C. for 1 h. The flexuralproperties were measured using ASTM D790. Table 6 shows the formulationand properties.

TABLE 6 Formulation No. 22 23 24 25 Components AroCy XU-366 100 100 100100 Noryl SA120 15 0 20 0 Noryl SA9000 0 20 0 25 Nonylphenol 6 6 3 3Chromium 0.15 0.15 0.15 0.15 acetylacetonate Crodamide ER 0 0 0.15 0.15Properties Dielectric Constant 2.683 2.665 2.665 2.660 (10 GHz) LossTangent (10 GHz) 0.0034 0.0031 0.0035 0.0030 T_(g) (° C.) 171.0 158.8165.0 170.8 Flexural Strength (MPa) 548 547 543 578 (710^(a)) FlexuralModulus (GPa) 21 22 19 21 (22^(a)) ^(a.)Laminate was made usingmachine-coated prepreg, whereas the other laminates were made usinghand-coated prepregs.

When introducing elements of the examples disclosed herein and theclaims below, the articles “a,” “an,” “the” and “said” are intended tomean that there are one or more of the elements. The terms “comprising,”“including” and “having” are intended to be open-ended and mean thatthere may be additional elements other than the listed elements.Although certain aspects, examples and embodiments have been describedabove, it will be recognized by the person of ordinary skill in the art,given the benefit of this disclosure, that additions, substitutions,modifications, and alterations of the disclosed illustrative aspects,examples and embodiments are possible.

1. A radome comprising a plurality of plies coupled to each other, inwhich at least one of the plurality of plies comprises a substrate and acured resin blend produced from an effective amount of a cyanate monomerand an effective amount of a cyanate ester oligomer to provide adielectric constant of less than 2.7, a glass transition temperature ofat least 150° C. and a moisture absorption of less than 1.5% for theradome, wherein the monomer is a compound of formulae (I)-(IX)

or mixtures of two or more cyanate monomers, wherein at least one of R¹and R² is —CN and the other of R¹ and R² is selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl, and wherein R³ and R⁴, whenpresent, are independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl.
 2. The radome of claim 1, in which the oligomer is a cyanateester oligomer comprising two or more monomeric units each selected froma compound having the formula (I)-(IX).
 3. The radome of claim 1,further comprising at least one phenol added to the resin blend.
 4. Theradome of claim 3, further comprising at least one metal catalyst addedto the resin.
 5. The radome of claim 1, in which the substrate comprisesone or more of a woven fabric, a non-woven fabric, a ceramic, a plastic,a glass, a fiberglass, a nylon, a polyester, a polyethersulfone, anaramid, a polyethylene, a polypropylene, a polyolefin, a polyimide, apolyamide, a polyamide-imide, a polyphenylene sulfide, a carbon, acarbon black, a graphite, a diamond, a polybenzimidazole, apolybenzoxazole or a halocarbon.
 6. The radome of claim 1, in which thecyanate monomer comprises a bisphenol dicyanate group and the cyanateester oligomer comprises a diphenylcyanate group.
 7. The radome of claim1, in which the monomer is present from about 30-70 weight percent. 8.The radome of claim 7, in which the oligomer is present from about 70-30weight percent.
 9. A prepreg comprising a plurality of plies coupled toeach other, in which at least one of the plurality of plies comprises asubstrate and a resin blend comprising an effective amount of a cyanatemonomer and an effective amount of a cyanate ester oligomer to provide acured resin comprising a dielectric constant of less than 2.7, a glasstransition temperature of at least 150° C. and a moisture absorption ofless than 1.5%, wherein the monomer is a compound of formulae (I)-(IX)

or mixtures of two or more cyanate monomers, wherein at least one of R¹and R² is —CN and the other of R¹ and R² is selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl, and wherein R³ and R⁴, whenpresent, are independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl.
 10. The prepreg of claim 9, in which the oligomer is acyanate ester oligomer comprising two or more monomeric units eachselected from a compound having the formula (I)-(IX).
 11. The prepreg ofclaim 9, further comprising at least one phenol added to the resinblend.
 12. The prepreg of claim 11, further comprising at least onemetal catalyst added to the resin blend.
 13. The prepreg of claim 9, inwhich the substrate comprises one or more of a woven fabric, a non-wovenfabric, a ceramic, a plastic, a glass, a fiberglass, a nylon, apolyester, a polyethersulfone, an aramid, a polyethylene, apolypropylene, a polyolefin, a polyimide, a polyamide, apolyamide-imide, a polyphenylene sulfide, a carbon, a carbon black, agraphite, a diamond, a polybenzimidazole, a polybenzoxazole or ahalocarbon.
 14. The prepreg of claim 9, in which the cyanate monomercomprises a bisphenol dicyanate group and the cyanate ester oligomercomprises a diphenylcyanate group.
 15. The prepreg of claim 9, in whichthe monomer is present from about 30-70 weight percent.
 16. The prepregof claim 15, in which the oligomer is present from about 70-30 weightpercent.
 17. A resin blend comprising an effective amount of a cyanateester monomer and an effective amount of a cyanate ester oligomer toprovide a cured resin comprising a dielectric constant of less than 2.7,a loss tangent of less than 0.004, a glass transition temperature of atleast 150° C. and a moisture absorption of less than 1.5, wherein themonomer is a compound of formulae (I)-(IX)

or mixtures of two or more cyanate monomers, wherein at least one of R¹and R² is —CN and the other of R¹ and R² is selected from hydrogen, —CN,—COOH, a hydrocarbon group comprising 1 to 6 carbon atoms, ahydrocarbonyl group comprising 1 to 6 carbon atoms, a halohydrocarbongroup comprising 1 to 6 carbon atoms, a halohydrocarbonyl groupcomprising 1 to 6 carbon atoms and phenyl, and wherein R³ and R⁴, whenpresent, are independently selected from hydrogen, —CN, —COOH, ahydrocarbon group comprising 1 to 6 carbon atoms, a hydrocarbonyl groupcomprising 1 to 6 carbon atoms, a halohydrocarbon group comprising 1 to6 carbon atoms, a halohydrocarbonyl group comprising 1 to 6 carbon atomsand phenyl.
 18. The resin blend of claim 17, in which the oligomer is acyanate ester oligomer comprising two or more monomeric units eachselected from a compound having the formula (I)-(IX).
 19. The resinblend of claim 17, further comprising at least one phenol added to theresin blend.
 20. The resin blend of claim 19, further comprising atleast one metal catalyst added to the resin blend.